Thanks max,
Now it's much clearer. I made the following experiment
>>>#1
>>> D={'a':1, 'b':2}
>>> D
{'a': 1, 'b': 2}
>>> E=D.copy()
>>> E
{'a': 1, 'b': 2}
>>> D['a']=3
>>> D
{'a': 3, 'b': 2}
>>> E
{'a': 1, 'b': 2}
>>>#2
>>> D={'a':[1,3], 'b':[2,4]}
>>> D
{'a': [1, 3], 'b': [2, 4]}
>>> E=D.copy()
>>
"Alex" <[EMAIL PROTECTED]> wrote in
news:[EMAIL PROTECTED]:
D={'Python': 'good', 'Basic': 'simple'}
E=D.copy()
E
> {'Python': 'good', 'Basic': 'simple'}
D['Basic']='oh my'
D
> {'Python': 'good', 'Basic': 'oh my'}
E
> {'Python': 'good', 'Basic': 'simple'}
>
> Hmm